Fuck sake.. Someone is either too young to have been through the major phase involving button fly jeans, or is too simple-minded to solve such an easy puzzle. You got access to the pants, that was the hard part!

Correction, engineers don't fuck. The engineer would look at the button fly jeans with interest in the materials and design. Immediately figure out how to undo them and totally ignore the panties since they were too simple. Said girl in now undone button fly jeans walks away, leaving engineer devastated. This is why Hentai came about.